//typedef类型定义语句
//typedef int Length;
//声明两个枚举类型
//表示可用的形状选项
typedef enum {
    kLineShape = 0,  // = 0 =1省略
    kRectShape,
    kEllipseShape,
    kImageShape
} ShapeType;
//表示可用的颜色选项
typedef enum {
    kRedColorTab = 0,
    kBlueColorTab,
    kYellowColorTab,
    kGreenColorTab,
    kRandomColorTab
} ColorTabindex;
#define degreesToRadian(x) (M_PI * (x) / 180.0)

